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TPS check

riverfever

NAXJA Forum User
By backprobing the sensor with a voltmeter I am getting .600 volts with the throttle closed. With WOT the meter shows 3.690 volts. Manual says I should have greater than 200 millivolts with the throttle closed and right at 4.8 volts with WOT. It looks like the TPS may be bad. Can I get a second opinion?

This is for a 96 4.0, auto.
 
Last edited:
Frank Z said:
What is the TPS input voltage the the connector removed from the TPS?
What is the signal voltage at the TPS with TPS connector disconnected (Use a straight pin to pierce the insulation at the connector near the PCM)?

Check for smooth change in resistance across the tps while slowly moving the throttle linkage from fully closed to fully open (WOT).

X2 on the questions. You need more data to confirm a bad TPS. The input voltage to the TPS should be near 5.0 volts. Check it at the TPS connector with TPS disconnected, and if it is low check again at the PCM to see if the low voltage is at the PCM or a loss in the wires between the PCM and TPS. Use an analog multi meter for the TPS smothness tested listed by FrankZ, a digital meter won't work for that test. The Smoothness test can be done with hot using the DC volts range, or power off using the ohms range.

INterssting that the 97 year allows the idle voltage to be as low as 0.20 volts. The 87-90 and I believe 91-95 years call for about 0.80 to 0.83 volts at idle depending on the FSM year.
 
riverfever,

Did you find out if the TPS was bad? Mine has been having problems at idle. I checked mine and it was .776v closed and 3.887v WOT with 5.13v going in. I've got a '96 too. I was thinking the WOT needed to be around 4.8v. Let me know if you fixed yours. Thanks.
 
Generally reference voltage will be 5.0VDC +/- 5%, throttle closed the voltage read will be .5-.8VDC and at WOT the voltage should read no more than 4.85VDC otherwise you will receive a TPS over voltage code.
As others have posted..... you can measure resistance across the ouput terminals by disconecting the harness from the TPS, use an analog multimeter on Ohms setting and verify the numbers increase and decrease smoothly otherwise this will indicate corrosion or cracks in the electrical contact surface of the TPS. IF it is corrosion... sometimes you can get a way with spraying electrical contact cleaner inside the TPS and rotate the TPS to clean the surfaces. This will work on occasion.....
 
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